Optical Profiles Research Articles

Development of a novel fibre optic beam profile and dose monitor for very high energy electron radiotherapy at ultrahigh dose rates

Objective. Very high energy electrons (VHEE) in the range of 50–250 MeV are of interest for treating deep-seated tumours with FLASH radiotherapy (RT). This approach offers favourable dose distributions and the ability to deliver ultra-high dose rates (UHDR) efficiently. To make VHEE-based FLASH treatment clinically viable, a novel beam monitoring technology is explored as an alternative to transmission ionisation monitor chambers, which have non-linear responses at UHDR. This study introduces the fibre optic flash monitor (FOFM), which consists of an array of silica optical fibre-based Cherenkov sensors with a photodetector for signal readout. Approach. Experiments were conducted at the CLEAR facility at CERN using 200 MeV and 160 MeV electrons to assess the FOFM’s response linearity to UHDR (characterised with radiochromic films) required for FLASH radiotherapy. Beam profile measurements made on the FOFM were compared to those using radiochromic film and scintillating yttrium aluminium garnet (YAG) screens. Main results. A range of photodetectors were evaluated, with a complementary-metal-oxide-semiconductor (CMOS) camera being the most suitable choice for this monitor. The FOFM demonstrated excellent response linearity from 0.9 Gy/pulse to 57.4 Gy/pulse (R 2 = 0.999). Furthermore, it did not exhibit any significant dependence on the energy between 160 MeV and 200 MeV nor the instantaneous dose rate. Gaussian fits applied to vertical beam profile measurements indicated that the FOFM could accurately provide pulse-by-pulse beam size measurements, agreeing within the error range of radiochromic film and YAG screen measurements, respectively. Significance. The FOFM proves to be a promising solution for real-time beam profile and dose monitoring for UHDR VHEE beams, with a linear response in the UHDR regime. Additionally it can perform pulse-by-pulse beam size measurements, a feature currently lacking in transmission ionisation monitor chambers, which may become crucial for implementing FLASH radiotherapy and its associated quality assurance requirements.

Optimal waveguide structure for low-threshold InGaN/GaN-based photonic-crystal surface-emitting lasers

We analyzed the optimal waveguide structure of two types of InGaN-based photonic crystal surface-emitting lasers (PCSELs) to suppress the coupling with leaky modes via mode simulations. To minimize the threshold material gain (gth), we calculated the confinement factor and quality factor of PCSELs with varying waveguide layer thicknesses in the separate confinement heterostructure (SCH) layer. The optical mode intensity profile revealed the coupling between the fundamental mode of SCH and parasitic leaky modes in the cladding layer or substrate as the primary root cause of the low-quality factor and high threshold gain of PCSELs. The asymmetric nature of the SCH structure yielded the optimal waveguide structure to be dependent on the position of the air holes. With a proper waveguide thickness and air hole depth, the optimized threshold modal gain of PCSELs with the n-side air holes can be less than 30 cm−1.

Preparation and properties of anti-reflective and anti-thermal shock of Y2O3/AlN composite films on CVD diamond

Y2O3/AlN composite films with different thicknesses of AlN interlayer were prepared on CVD diamond by RF magnetron sputtering. The influence of AlN thickness on the microstructure, adhesion strength, film stress, thermal shock resistance and infrared transmittance of the films was investigated by X-ray diffractometer, scanning electron microscopy, scanning probe microscopy, UV–Vis spectrophotometer, Fourier transform infrared spectrometer, scratch tester and 3-D optical surface profiler. The results show that CVD diamond coated with Y2O3/AlN composite films with different thicknesses of AlN have different degrees of anti-reflective effects in the 8–10 μm infrared band. The adhesion strength and quality of the composite film were improved with the AlN thickness increased, and the anti-reflective and anti-thermal shock of the film showed a trend of first increasing and then decreasing. CVD diamond coated with Y2O3/AlN composite films with 700 nm AlN interlayer has an average transmittance of 77 % in the 8–10 μm band and a good adhesion between interfaces. It can withstand rapid temperature changes and effectively protect the diamond substrate with little or no degradation of infrared optical properties.

Synthesis, NMR, electronic properties using DFT study and anticancer activity of 3-methyl-6-(m-tolylamine) quinazolin-4(3H)-one

3-methyl-6-(m-tolylamine) quinazolin-4(3H)-one (MTAQ) was synthesized. Its formation was ascertained with the help ESI mass spectroscopy in conjunction with 1HNMR spectroscopy. Anticancer activity of MTAQ was measured experimentally, for human carcinoma cell line pertaining to cervix (HeLa). Optimized structure parameters, Frontier molecular orbital (FMO) behavior, non linear optical (NLO) profile, molecular electrostatic potential surface (MESP), Fukui functions (FF) and thermodynamic parameters were evaluated for the molecule of interest employing DFT/B3LYP/6–311++G(d,p) formalism. TD-DFT was made use of to calculate absorption maxima (λmax) of electronic transitions for the molecule in CDCl3 solvent. Frontier molecular orbitals revealed the origin of UV–Vis spectrum and to comprehend chemical reactivity of the molecule. Good coincidence was noticed between measured and computed structure parameters, UV–Vis spectra, and 1HNMR signals. Fukui functions helped in identifying electrophilic and nucleophilic centers of MTAQ. The calculations showed that MTAQ exhibits significant NLO activity in addition to predicting existence of intramolecular hydrogen bond.

The smallest structures in Saturn’s rings from UVIS stellar occultations

On the largest scales Saturn’s rings are often thought of as axisymmetric annuli varying only radially in optical depth with exceptions of spiral waves and eccentric ringlets. But on scales smaller than a few tens of km yet still larger than the largest common ring particles, the assumption of azimuthal symmetry breaks down. Structures such as “straw” in the troughs of density waves, partial gaps around propeller moonlets, and ephemeral particle aggregates such as self-gravity wakes are responsible for the predominant variations in optical depth. During the 13 year Cassini mission, the Ultraviolet Imaging Spectrograph (UVIS) high speed photometer (HSP) measured 80 stellar chord occultations of Saturn’s main rings. In the vicinity of the minimum ring plane radius of each chord, the occultation line-of-sight slewed across the ring plane tangent to the Keplerian motion of the ring particles. These occultations measured ultraviolet light in the wavelength range 110–190 nm with 1- or 2-ms ms integration times, providing optical depth measurements with resolution comparable to the Fresnel scale of ∼10 m in the frame co-moving with the local Keplerian speed. These high-resolution chord occultations reach their minimum ring radii over a broad range of radial locations within Saturn’s main rings and resolve non-axisymmetric structures in a wide variety of ring regions. We measure the azimuthal length scales and optical depth profiles of “ghosts”, or azimuthally limited gaps with radial scales less than 30 m (Baillié et al., 2013), in the C ring plateaus. We measure the length scale of transparent gaps and self-gravity wakes in the peaks and troughs of spiral density waves. We present optical depth profiles which resolve axisymmetric waves in the A and B rings and constrain the azimuthal length scale over which the waves remain axisymmetric to ∼1000 km. We combine autocorrelation length scales from stellar occultations which cut across the minimum ring radius of a chord occultation with line-of-sight trajectories from other occultations which are not tangent to the rings to constrain the morphology of the azimuthally and temporally averaged mesoscale structures at that ring radius. 2D autocorrelation profiles from stellar occultations show self-gravity wakes and axisymmetric waves often coexisting.

Исследование качества молодых игристых вин из крымских автохтонных сортов винограда

Most domestic sparkling wines are made of traditional champagne grape varieties. However, indigenous Crimean cultivars could increase the output of high-quality original beverages if a proper technology was introduced. 
 This research featured young sparkling wines from Crimean grape varieties, i.e., Soldaya, Shabash, Kokur Beliy, Sary Pandas, Kefesiya, Dzhevat Kara, and Ekim Kara. Organic acids, sugars, glycerin, phenolic substances, and ethanol were determined by high performance liquid chromatography; the content of amine nitrogen was measured by formalin titration. The optical profile of the wine samples was subjected to the colorimetric method while their foamy properties were studied by bubbling the samples in a measuring cylinder. The sparkling properties depended on the rate of CO2 desorption; the volumetric method made it possible to define the CO2 content; the viscosity was measured using a viscometer. The sensory assessment followed State Standard 32051-2013, ISO 5492:2008, and ISO 11035:1994. 
 The samples of Kokur Beliy, Sary Pandas, and Soldaya received high tasting ratings (≥ 9.0 points), as did the red variety of Kefesiya (8.95 points). They demonstrated a clear typical aroma and a harmonious taste, as well as good foamy and sparkling properties. The maximal foam volume correlated with amine nitrogen (r = 0.762) while the sparkling properties correlated with the mass fraction of bound CO2 (r = 0.977). The red sparkling wine from the Kefesiya variety had a dark garnet color due to its high anthocyanins. It also contained quercetin and glycoside, which are known for their biological (P-vitamin) activity and powerful antioxidant properties. The early low-sugar (< 18 g/100 cm3) varieties of Dzhevat Kara and Ekim Kara had the same acidity but demonstrated a less diverse phenolic profile and were paler in color. 
 In this research, the indigenous Crimean grape cultivars of Kokur Beliy, Sary Pandas, Soldaya, and Kefesia showed good prospects for young sparkling wines. Other varieties needed special technologies to preserve their typical properties and the aroma/taste balance. The new technology makes it possible to obtain unique high-quality products right in the harvest year, thus increasing the range and volume of sparkling wine production.

Regulating loading strain rates under shockless quasi-isentropic compression using a resin-based areal density gradient flyer

Areal density gradient flyers (ADGFs) have important applications in quasi-isentropic compression and high strain rate loading. The wave impedance gradient distribution of the reported ADGFs is single, and the effects of different wave impedance gradient distributions and spikes number density on the loading results are unknown. In this study, the resin-based ADGFs with different spike areal density distribution and spikes number density were designed and prepared using projection micro stereolithography technology (PμSL). The printing accuracy of ADGFs was evaluated using three-dimensional optical profiler, optical microscope, Scanning Electron Microscopy (SEM) and ultra depth of field microscope. The loading process of the ADGF on the target was studied by experiment and simulation. The simulation result was consistent with the experimental result. Augmenting the wave impedance distribution index (P) of spikes and spikes number density increases the loading strain rate. Due to the high printing accuracy of PμSL, the fine ADGF structures with large spikes number density can be prepared, thereby promoting the formation of quasi-isentropic compression plane waves. This work realizes the regulation of loading strain rate under shockless quasi-isentropic compression, which is significant for understanding the mechanical response of materials under high strain rate loads.

Origin of Black Color in Heavily Doped n‐Type GaN Crystal

In semiconductor materials, doping is used mainly for controlling the electrical properties. There have been attempts to grow low‐resistivity n‐type gallium nitride (GaN) crystals by doping oxygen, germanium, and silicon, because a low‐resistivity GaN substrate is required to reduce the power losses of optical and electrical devices. However, in those efforts, the crystal color turns black with the increase in the concentration of the n‐type additives, even though they are shallow donors. Herein, it is explained why heavily doped n‐type GaN crystals exhibit low transparency. From optical absorption profiles, the appearance of a band tail from the band edge to 1.5 eV is observed. Considering the band tail theory and our observations, it is concluded that Ga vacancy or Ga vacancy complexes behaving as acceptors induce the band tail and the black color. It is proposed that neutralizing the high charge of defects ensures that low‐colored GaN crystals with low resistivity can be obtained. Moreover, the fabrication of low‐resistivity wafers sliced from a large crystal with a laser produces inexpensive wafers and allows the spread of high‐efficiency GaN devices fabricated on low‐resistivity substrates for saving electric power.

Registration of hyperspectral images and mass spectrometry data for the correlation of tissue optical spectra and molecular profiles.

Hyperspectral imaging (HSI) is a label-free imaging modality that is emerging for non-invasive detection of various diseases including cancers. HSI provides high-resolution spatial images where each pixel has a spectral curve with numerous wavelength bands from the visible to infrared ranges. The rich spatial and spectral information can be used to discriminate various types of tissues and pathophysiological conditions. However, it can be difficult to explain spectral data with respect to the underline cellular and molecular mechanism. In this study, we developed an approach that registers hyperspectral images and mass spectrometry (MS) data where MS provides tissue molecular profiles. Human prostate tissues that were obtained after prostatectomy were used in the experiments. The whole prostate was first sliced every six mm. A customized hyperspectral surgical microscope was used to acquire HSI data from the sliced tissue. For MS data analysis, the sliced tissue of the prostate was divided into 51 small regions and then processed separately for each region. The immediately adjacent tissue was sliced and processed histologically for H&E staining. The MS molecular profiles were correlated with the hyperspectral images in this study.

Fundamental characteristics of biomimetic superhydrophobic surface of nitinol alloy fabricated via laser cauterization and FAS modification

Biomimetic superhydrophobic surfaces draw inspiration from the biological realm, seeking to replicate and refine their superhydrophobic properties. Fabricating super-hydrophobic surface on nitinol has significant application value in medicine, biomedical science, industry, and micro electric system due to the special performance of this material with super-hydrophobicity. In this study, we achieved a super-hydrophobic surface on a laser-processed rough nitinol surface through FAS modification, and its corrosion resistance in salt electrolytes was evaluated using potentiodyjnamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) measurements. The resulting indicated that the fabricated super-hydrophobic surface exhibited superior corrosion resistance performance. Besides, the mechanical properties of the material were also evaluated, revealing a reduction in contact angle by 2.04 and 2.82 times as well as enhanced wear its resistance. Furthermore, the promoting mechanism of chemical and abrasion stability were systematically elucidated based on scanning electron spectroscopy (SEM-EDS), 3D optical profiling, and X-ray photoelectron spectroscopy (XPS). These findings are anticipated to provide a deeper understanding of the fabrication of super-hydrophobic surfaces on nitinol alloys, thereby strengthening their potential for practical industrial and biomedical applications.

Study on gear contact stiffness and backlash of harmonic drive based on fractal theory

Contact stiffness and backlash in the harmonic drive significantly impact a robot's positioning accuracy and vibration characteristics. The height of the harmonic drive tooth pair is typically less than 1 mm, making the measurement and modeling of backlash and contact stiffness inherently complex. This paper proposes a contact stiffness and backlash model by establishing a correlation between fractal parameters and tooth contact load. To obtain the fractal roughness parameters of the real machined tooth surface, a combination of a noncontact optical profiler and the RMS method is employed. Subsequently, the study explores the influence of rough tooth surface and contact force fractal parameters on contact stiffness and gear backlash. The results demonstrate the substantial impact of surface topography parameters and contact force on contact stiffness and backlash. Specifically, an increase in the fractal dimension correlates with a reduction in gear backlash and contact stiffness. Conversely, the fractal roughness parameter exhibits the opposite effect. Notably, an increase in contact force enhances contact stiffness.

Assessing the reinforced molecular/mechanical behaviors of GOs@Mo-MOFs films deposited via electrophoresis onto microdevices: Experimental and theoretical perspectives.

One of the primary hurdles in microdevice fabrication lies in ascertaining the most impactful tactics for adapting metal surfaces. Through a one-pot tackle and distinct mechanochemical reactions evoked by 15minaqueous wet sand-milling (SM-15), we successfully grafted Mo-based metal-organic frameworks (Mo-MOFs) onto graphene oxides (GOs). Following this, a convenient and readily scalable methodology of electrophoretic deposition was implemented to create controllable thickness of SM-15 GOs@Mo-MOFs lubricating films, achieving considerable enhancements of 143% and 91% in hardness and Young's modulus, respectively, when compared to those of SM-15 Mo-MOFs. The successful synthesis of SM-15 GOs@Mo-MOFs was corroborated using strategies such as x-ray diffraction, Fourier transform infrared spectroscopy, and field emission scanning electron microscopy. Analyses using the micro-tribotester indicated that the new film exhibited a lowest friction coefficient of roughly 0.5 when imposed with a load of 5 N and sliding speed of 8 mm/s. In addition, the optical profiler nano-indentation in situ scanning probe microscope revealed that SM-15 GOs@Mo-MOFs films had smaller and shallower scratches and grooves compared to SM-15 Mo-MOFs ones. The calculated results of key descriptors (EHOMO, ELUMO, ΔE, etc.) in density functional theory quantitatively disclosed the interaction mechanisms between GOs@Mo-MOFs molecules and microdevices. We first scrutinized the innate properties of molecule adsorption energy and frictional mechanical behaviors using synergetic cross-scale simulations, such as Monte Carlo and finite element methods. The expectation was that this process would motivate a valuable technique for shielding in the thriving micromanufacturing.

Synergistic effects of melamine functionalized graphene oxide and imidazolium ionic liquid on the tribological performance and thermal stability of polyalphaolefin based hybrid nanolubricants

Tribological and thermophysical characteristics of a new hybrid nanolubricant that incorporates melamine functionalized graphene oxide (mGO) and imidazolium cation based ionic liquid (IL) in a polyalphaolefin (PAO-6) base oil have been investigated. Different formulations of nanolubricants with 0.05 wt%, 0.1 wt% nanosheets and 1 wt% ionic liquid were studied to examine the synergistic effects of surface functionalization and ionic liquid addition on the antifriction and antiwear properties of the PAO-6 base oil. Thermal stability studies involved Thermogravimetric analysis to analyze the oxidation onset and decomposition temperature of different formulatons at varying weight concentrations of nanoadditives. Anti-friction performance was quantified by the coefficient of friction (COF) reduction compared to neat lubricant. The highest reduction in COF was observed for 0.05 wt% mGO + 1 wt% IL with an outstanding 73.33% reduction followed by 0.05 wt% mGO and 0.05 wt% GO with 73% and 67% reduction respectively. Post-wear analysis of the wear scars was performed using 3D optical profiler, SEM micrographs, EDX elemental composition and Raman spectra. The highest reduction in wear depth was observed in the case of PAO-6 + 0.05% mGO with a value of 46.3% followed by a 39.9% reduction in the case of PAO-6 + 0.05% GO. The morphologies of samples containing both ionic liquid and nanosheets exhibited a much smoother surface with the absence of deep grooves and pits which was attributed to the formation of a strongly bonded tribofilm owing to the chemical interactions between ionic liquid capped nanosheets and metal substrate. Strong interfacial interactions also induced a significant increase in the thermal stability of the nanofluids. The maximum shift observed in the oxidation onset temperature compared to neat PAO-6 was 68◦C while the decomposition temperature increased by 61◦C. Due to their excellent friction, wear, and thermal properties, these hybrid nanofluids could be applied in various highly demanding industrial sectors such as automotive, machining operations, aerospace, thermal power plants and micro/nano-electromechanical systems.

Identifying reliable periods in 2MASS J09213414–5939068, IGR J16167–4957, and V667 Pup

Detailed timing analyses of three cataclysmic variables, namely 2MASS J09213414−5939068, IGR J16167−4957, and V667 Pup are carried out using the long-baseline and high-cadence optical photometric data from the Transiting Exoplanet Survey Satellite (TESS). Periods of 908.12 ± 0.05 s and 990.10 ± 0.06 s are observed in the optical variation of 2MASS J09213414−5939068 that were not found in earlier studies and appear to be probable spin and beat periods of the system, respectively. The presence of multiple periods at spin, beat, and other sidebands indicates that 2MASS J09213414−5939068 likely belongs to an intermediate polar class of magnetic cataclysmic variables that seems to be accreted via a disc-overflow mechanism. Clear evidence of a period of 582.45 ± 0.04 s is found during the TESS observations of IGR J16167−4957, which can be interpreted as the spin period of the system. Strong modulation at this frequency supports its classification as an intermediate polar, where accretion may primarily be governed by a disc. The dominance of the spin pulse unveils the disc-fed dominance accretion in V667 Pup, but the detection of the previously unknown beat period of 525.77 ± 0.03 s suggests that a portion of the material is also accreted through a stream. Moreover, the double-peaked structure observed in the optical spin pulse profile of V667 Pup suggests the possibility of a two-pole accretion geometry, where each pole accretes at a different rate and is separated by 180°.

Comparison of Distance-Based Uncorrected Visual Acuity Based on the Optical Profile of Same Platform IOLs.

To compare and evaluate uncorrected visual acuity (UCVA) from far to near distance for four different optical designs of intraocular lenses (IOLs), developed on the same IOL platform. In a cohort of 121 patients, who underwent uncomplicated cataract surgery in Zengyo Suzuki Eye Clinic, Japan, between June 2018 and November 2023, and who received a single-piece TECNIS OptiBlue™ platform series IOL, the following four groups were established based on the IOL implant type: ZCB00V (TE), ZXR00V (SF), DFR00V (SG), and DIB00V (EH). UCVA at 5 m, 1 m, 70 cm, 50 cm, 40 cm, and 30 cm, as well as contrast sensitivity (with and without glare), was compared at one month post-operation. Regarding diffractive IOLs, patients in the SG group demonstrated significantly improved visual acuity at 5 m, 50 cm, 40 cm, and 30 cm, while those in SF group performed significantly better at 1 m. Among non-diffractive IOLs, patients in the EH group demonstrated significantly improved visual acuity scores at 1 m, 70 cm, 40 cm, and 30 cm, compared to individuals in the TE group, with comparable results between the two groups at 5 m and 50 cm. Patients in the SF and EH groups achieved similar results for visual acuity and contrast sensitivity, while those in the SG group exhibited a distinctive decrease in contrast sensitivity (with glare) relative to the other three groups. DFR00V seemingly provides excellent UCVA from near to far distances, aiming for spectacle independence, although at the potential cost of decreased contrast sensitivity compared to the other three IOL types. Furthermore, although ZXR00V and DIB00V differ lens structures, they may nonetheless provide similar visual quality and spectacle independence in daily life.

Chemical state and atomic structure in stoichiovariants photochromic oxidized yttrium hydride thin films

Abstract We investigate the effective oxidation state and local environment of yttrium in photochromic YHO thin film structures produced by e-beam evaporation, along with their chemical structure and optical properties. Transmission electron microscopy images reveal the oxidized yttrium hydride thin film sample exhibiting a three-layered structure. X-ray photoelectron spectroscopy (XPS) measurements manifest that the oxidation state of yttrium is modified, dependent on the film’s composition/depth. Furthermore, Ion beam analysis confirms that this variability is associated with a composition gradient within the film. X-ray absorption spectroscopy at the Y K-edge reveals that the effective oxidation state of yttrium is approximately +2.5 in the transparent/bleached state of YHO. Spectroscopic ellipsometry investigations showed a complex non-linear optical depth profile of the related sample confirming the dominant phase of YHO and the presence of Y2O3 and Y towards the middle of the film. The first evidence of (n; k) dispersion curves for e-beam sputtered photochromic YHO thin films are reported for transparent and dark states.

Comprehensive profile and areal calibration by additively manufactured material measures

Abstract The calibration of surface texture measuring instruments is standardized with two distinct types of material measures. ISO 25178-70 categorizes material measures that feature a profile and an areal surface topography. The result is that different types of measuring instruments like profilers on the one hand and areal surface topography measuring instruments on the other hand may require different material measures whose scope of application may be limited to only one of the named instrument types. The reason is that most manufacturing principles allow either a linear or circular extrusion of a geometry limiting the possibilities to manufacture material measures that are suitable for both, profile and areal surface topography measuring instruments. Since a comparability is desired for as many different measuring instruments as possible, we examine to what degree profile and areal material measures of ISO 25178-70 can be adapted and combined to possibly allow a calibration of all types of surface topography measuring instruments. Additive manufacturing with direct laser writing (DLW) is characterized by a high degree of freedom in the design of material measures. An enhancement of structures that can be imaged either in multiple lateral directions or extruded to circular geometries is possible, allowing both, a profile sampling in different directions, just as well as an areal measurement. In the present publication, a modification of the ISO 25178-70 material measures is described including the design process, the manufacturing and the measurement with areal and profile surface topography measuring instruments to practically demonstrate the feasibility of a multifunctional calibration that considers the possible effects of directionality. We show that it is possible to combine different profile and areal geometries by linear and/or areal extrusion of the corresponding profile-based geometry. By aligning multiple material measures onto one sample, it can also be demonstrated that a comprehensive calibration of an optical profiler is enabled with only one measurement.

Influence of magnesium chloride on the electrodeposition of zinc from the 1,3-dimethyl-2-imidazolidinone/ZnCl2 system

The effect of magnesium chloride (MgCl2) on the electrodeposition of zinc in 1,3-dimethyl-2-imidazolidinone (DMI)/ZnCl2 solvate ionic liquids was investigated. Cyclic voltammetry and Chronoamperometry are employed to study the electrochemical behavior of Zn. The crystal structure, microscopic morphology, and roughness of Zn coatings were measured by X-ray diffraction (XRD), scanning electron microscopy (SEM), and Non-contact Optical Surface Profiler (OSP). The results reveal that adding MgCl2 is favorable to the electrodeposition of Zn and leads to the formation of a new zinc-containing species in the electrolyte, which was confirmed by Raman spectra. Importantly, this addition does not affect the nucleation mechanism of zinc. Furthermore, the zinc grows preferentially on the (101) plane and a more smooth and uniform zinc coating was obtained. Corrosion resistance testing is conducted in a 3.5 wt% NaCl solution using the Tafel method. Coatings obtained at 4 mA/cm2 and 343 K with 0.1 mol/L MgCl2 addition exhibit lower corrosion current density of 38.10 μA/cm2 compared to zinc coatings obtained without MgCl2.

Robotic measurement system based on cooperative optical profiler integrating fringe projection with photometric stereo for highly reflective workpiece

Robotic measurement has emerged as a prominent method for the quality control of large-scale metal workpieces. However, it faces two significant challenges: optical measurement of homogeneous high-reflective metal surfaces and point cloud registration on local featureless surfaces. To address these challenges, this study presents a cooperative optical profiler that integrates a certain number of light-emitting diodes into a conventional fringe projection profiler. This integration enables the use of photometric stereo, providing comprehensive and accurate surface normals of machined metal surfaces with intricate details such as tool marks. The surface normal was then fused with the initial point cloud from the fringe projection profiler to yield complete local measurement results. In addition, a geometry descriptor incorporating the surface normal was designed to improve data registration accuracy. Experiments based on six small workpieces with the combination of three shapes and two materials and a large freeform workpiece demonstrated that the proposed method achieved measurement accuracy close to that of a coordinate measuring machine.

Comparison of modal and zonal wavefront measurements of refractive extended depth of focus intraocular lenses.

Extended depth-of-focus (EDoF) intraocular lenses (IOLs) are typically evaluated using commercially available aberrometers. Given the intricate optical design of these IOLs, employing an appropriate wavefront reconstruction method with a sufficient sampling resolution of the aberrometer is crucial. A high-resolution Shack-Hartmann wavefront sensor was developed by magnifying the pupil aperture by a factor of five onto a lenslet array (pitch: 133 µm) and utilizing a full-frame CMOS sensor (24 by 36 mm), resulting in a 26.6 µm sampling resolution. Zonal wavefront reconstruction was used and compared with Zernike-based modal wavefront reconstruction to retain detailed local slope irregularities. Four refractive EDoF IOLs with a power of 20D were examined, and the wavefront difference between the zonal and modal methods, expressed as the root mean squared error (RMSE), remained significant for two of the IOLs up to the 16th-order Zernike spherical aberrations (SAs). Conversely, a negligibly small RMSE was observed for the other two IOLs, as long as the Zernike SAs were higher than the 6th order. The raytracing simulation results from the zonal wavefronts exhibited a stronger correlation with the results of recent optical bench studies than those from the modal wavefronts. The study suggests that certain recent refractive EDoF IOLs possess a complex optical profile that cannot be adequately characterized by limited orders of SAs.